Apparatus for controlling a pressure cooker



June 14, 1955 R. .1. wAGNER ETAL '217143627 APPA RATUS FOR CONTROLLING APRESSURE CQOKER Filed June 12, 1951 111116112 0715 Kobe/IJ United StatesPatent APPARATUS FOR CONTROLLING A PRESSURE COOKER Robert I. Wagner,Philadelphia, and Harvey E. Hartman, Jr., Southampton, Pa., assignors toProctor Electric Company, Philadelphia, Pa., a corporation ofPennsylvania Application June 12, 1951, Serial No. 231,225

2 Claims; (Cl. 137-540) This invention relates to apparatus forcontrolling the pressure of a pressure source, and more particularly theinvention relates to apparatus for controlling a pressure cooker.

In the copending Turner et al. application Serial No. 777,496, filedOctober 2, 1947, now Patent No. 2,641,`680, issued June 9, 1953, thereis disclosed and claimed an automatic pressure cooker apparatuscomprising a control mechanism and a pressure cooking vessel adapted tobe brought into cooperative relation with one another, the pressurecooking vessel being equipped with a valve having a freely movable valveVelement projectable by pressure within said vessel, and the controlmechanism including a spring-biased element engageable by said valveelement. Through the inter-engagernent of the said elements, theoperation of the pressure cooker is caused to be fully automatic undercontrol of the said mechanism, requiring merely that the user set acontrol knob or dial to a selected setting for a desired cookng time.

In our copending application Serial No. 231,224, filed the user Vreducethe heat input when the pressure within the cooker reaches the desiredcooking pressure, and it is also necessary that the user commence timingthe cooking operation when the cooking pressure is reached. However, thevalve employed on the pressure cooker of the above-mentioned apparatusis not in itself adapted for non-automatic use of the pressure cooker.

The principal object of the present invention' is to provide a devicewhich will enable non-automatic operationA of the pressure cooker of theabove apparatus, not only 'extending the usage of such apparatus butalso making it possible for `a prospective user to first buy thepressure cooker itself and use it non-automatically, and laterbuy 'thecontrol stand containing the control mechanism'wheneverit is convenientto do so.

Another: object of this invention is to provide a novel valve adapter'bywhich the pressure cooker of the abovementioned apparatus may be usednon-automatically apart from the control mechanism.

Still another object of this invention is to provide a novelvalveadapter which will control the operation of the valvev so as to causepressure build-up within the pressure cooker to a desired cookingpressure, and which will give an indication to the user when the cookingpressure is reached.

A further object of the invention is to provide a novel combination ofa' valve and a pressure-controlling cap structure, which combinationwill perform the above- ICC mentioned functions and will also vent anyexcess pressure in the event that the pressure Within the cooker vesselrises above the cooking pressure.

Other objects and features of the invention will be apparent from thefollowing detailed description with reference to the accompanyingdrawing, wherein:

Fig. 1 is a cross sectional view of the pressure cooker: valve and theadapter provided by this invention, showing the movable parts inpositions they assume prior to pressure build-up within the cookervessel;

Fig. 2 is a similar view showing the movable parts in the positions towhich they move upon attainment of the cooking pressure within thecooker vessel;

Fig. 3 is a sectional view taken along line 3-3 of Fig. l;-

Fig. 4 is a fragmentary sectional view taken along line 4-4 of Fig. 3;

Fig. 5 is a perspective sectional view of the cap employed in the capstructure;

Fig. 6 is a perspective view of the closure member employed inconjunction with the cap; and

Fig. 7 is a perspective view of the movable member employed in the capstructure.

Referring first to Figs. 1 and 2, there is shown a por-l tion of the lid10 of a pressure cooker equipped with a' valve 11 of the Characteremployed in the apparatus hereinbefore mentioned. In the illustratedform of the valve, the valve casing comprises parts 12 and 13 which'cooperatively form a chamber 14. Part 12 is formed to seat in an opening15 of the pressure cooker lid 10 and has a threaded annular extension 16which is threadedly engaged by a collar 17, the latter serving to holdthe part 12 in place. Part 13 is also threadedly engaged with the collar17 and has an upwardly-extending annular projection 18, which abuts withthe annular extension 16 of the upper part 12.

Part 13 is provided with transverse passages 19, and it is formed so asto provide restricted annular passage spaces 20 and 21 between it andthe lower part of collar 17, said spaces leading to the passages 19. Theupper portion of part 13 is also formed to provide an inletV port 22 forthe valve chamber 14, so that said chamber is in communication with theinterior of the cooker vessel.

Part 12 is formed to provide an outlet port 23 for chamber 14 and alsoto provide a passage 24 leading from the outlet port to an outletopening 25. v

Within the valve chamber 14 is a pressure plate 26 .t which is freelymovable vertically in said chamber. This plate' is preferably in theform of a disk of smaller diame-` ter than the internal diameter ofchamber 14, and the plate has a central'aperture 27 and a surroundingportengaging portion 28. Extending through the aperture 27 of the plateis an axially movable stem 29 having a shoulder 30 whichl engages theupper edge of the aperture 27 so as to normally close said aperture. Theupper secton 31 of the valve stem, although larger in diameter than thelower section 32, is of smaller diameter than the Outlet passage 24 andextends through a restricted opening 33 in part 12 exteriorly of thevalve structure. The lower section 32 of the valve stem extends througha restricted aperture 34 of part 13. Thus, the valve stem is supportedand guided for Vertical axial movement.

z The lower end of the stem is swaged as shown at 35,

thus providing an extreme upward limit of movement of the stem.

A valve of the Character illustrated and above described, while usablein conjunction with apparatus such as hereinbefore mentioned forautomatic control of a valve by itself in non-automatic operation of thepressure cooker, the movable valve parts would rise under the infiuenceof relatively low pressure within the cooker' vessel, but would not berestrained in the manner necessary to effect a pressure seal, andtherefore the pressure could not rise to the cooking pressure which isusually in the neighborhood of fifteen pounds.

In accordancc with the present invention, there is provided an adapterin the form of a cap structure which s removably applicable to the valveand which serves to render the valve usable for non-automatic operationof the pressure cooker.

Referring further to the drawing, in the preferred form illustrated, theadapter comprises a cap 36 which may be formed of a material such asBakelite having low heat conductivity, a closure member 37 for the mouthend of the cap which may be formed of thin sheet metal, apressure-actuated member 38 which may be formed of a material such asBakelite having low heat conductivity, and a helical spring 39 formed ofWire of appro- 2' priate size and design to give a desired pressure Whencompressed, as hereinafter described. As may be seen in Figs. 3 and 5,the mouth portion of the cap 36 is formed to provide a pair ofdiametrcally opposed internal recesses 40 and a number of other smallerinternal recesses 41, all of the recesses extending inwardly from themouth end of the cap and terminating at an internal shoulder 42. Theclosure member 37 is in the form of a thin sheet metal disk having acentral aperture 43,

a pair of diametrically opposed spring fingers 44, and .'I

a number of tabs corresponding in number and position to the recesses 41of the cap 36. The disk-shaped member 37 is of such size that it may beinserted within the month portion of the cap 36 to `seat against theshoulder 42, with the spring fingers 44 disposed in recesses 40,

and with the tabs 45 disposed in recesses 41. The tabs 45 are of suchlength that they frctionally engage the walls of recesses 41 and serveto lock member 37 in place.

Prior to the insertion of the closure member 37, however, the helicalspring 39 and the pressure-actuated member 38 are inserted within thecap 36, as shown in Figs. l and 2. Then when the closure member 37 isinserted, the entire assembly forms a unitary device which may beapplied to the pressure cooker valve whenever it is desired to operatethe pressure cooker nonautomatically. As shown in Figs. l and 2, part 12of the valve 11 is provided with an annular recess 46, and the springfingers 44 are bent to form end portions which seat in said recess. Thecap recesses 40, which accommodate the spring fingers 44, aresufliciently large to permit fiexing movement of the spring fingers asthe adapter device is applied to or removed from the valve 11.

The pressure-actuated member 38 comprises a disk-like portion 47 and astem-like portion 48. The disk-like portion 47 has a central recess 49to seat the end of the valve stem 31, and the said portion also has aperipheral fiange 50 to seat the lower end of the helical spring 39. Thecap 36 is provided with a central aperture 51 at its top, through whichthe stem-like portion 48 extends, and the cap is also formed to providean annular recess 52 to seat the upper end of the spring 39.

Considering the operation of the device, 'normally the movable parts arein the positions shown in Fg. l and the helical spring 39 issufficiently compressed 'to provide a predetermined opposing force toupward movement of the valve stem 29, preventing upward movement of thestem until the pressure within the cooker vessel attains a predeterminedvalue. It will be noted that the inner edge portion of the plate 26slightly overhangs the edge of the valve inlet port 22, and when thepressure within the cooker vessel rises to a predetermined value,preferably less than the .full .pressure for the cooking operation, thepressure `on the over-hanging .edge portion of the pressure plate 26breaks the seal and moves the pressure plate and the valve stem upwardsufficiently to uncover the port 22, whereupon the pressure is appliedover the full area of plate 26 and both it and the valve stem are movedrapidly upward to the position shown in Fig. 2, thus sealing the outletport 23. The upward projection of the valve stem causes the stem-likeportion 48 of member 33 to be projected upwardly above cap 36, and thisindicates to the user that it is time to reduce the heat input and tocommence timing the cooking operation. Preferably member 38 is of adistinctive bright color, such as bright red, so as better to attractthe attention of the user. At this time, the spring 39 is furthercompressed and exerts a predetermined down- Ward pressure on the valvestem. The cooker pressure is applied to the shoulder 30 but the springresists further movement of the valve stem 29 as long as the pressuredoes not exceed full cooking pressure. Accordingly, the pressure ispermitted to rise to the full cooking pressure.

During the pressure cooking operation, if the pressure within the cookervessel should rise above the desired cooking pressure, the valve stem 29will rise, as indicated by the dotted line showing in Fig. 2, the spring39 being inetfective to prevent the movement of the stem under theexcess pressure exerted on the shoulder 30 through the aperture 27 ofplate 26. The rising of the valve stem uncovers the said aperture andcauses pressure venting through the passage 24 and outlet 25 until thepressure within the cooking vessel decreases substantially to thedesired cooking pressure, at which time the valve stem is lowered by theforce of spring 39 to close the aperture 27.

By the present invention, the user is apprised to start the timing ofthe cooking operation at a certain pressure. preferably lless than thedesired full cooking pressure. The early starting of the timing acts tocompensate for any cooking that is done during the heating up operation.The user is also apprised that the heat should be reduced and cantherefore prevent excessive steam loss due to overshoot. In theembodiment shown, member 38 will move to the position of Fig. 2 onattainment of approximately 8 p. s. i. cooker pressure. This is thevalue chosen for an Operating cooking pressure of l5 p. s. i. Attainmentof pressures in excess of 15 p. s. i. causes rising of valve stem 29 tothereby vent the steam through passage 24 and Outlet 25. As With theusual non-automatic cooker, the user reduccs the heat to a valuesufficient to maintain a slight interrnittent steam venting.

At the end of the timed cooking operation, the user removes theVpressure cooker from the source of heat or turns the heat off, and thepressure within the cooker may be reduced by one of several procedures.The cooker may be cooled by running water thereon, or down- Wardpressure may be manually applied to the stem-like portion 48 in anamount sutfieient to move the plate 26 to an intermediate position inChamber 14, thus causing the pressure to be vented around said plate andthrough the valve ports. A preferred procedure is to manually remove theadapter from its position on top of valve 12. This permits the stem 29to rise to its topmost position as determined by its swaged end 35. Thestem vents through the annular orifice 24 and out opening 25. The rateof steam release through orifice `24 is determined by the area of theannulus. The orifice provided permits a rate of steam release far lessthan that of existing commercial devices. The danger of sudden pressurerelease that might result from large orifice areas is eliminated.Further, the danger of clogging is greatly reduced by the use of lowerventing rate. In any case the design of the peripheral inlet opening 20practically eliminates blocking or Coverage by food particles, e. g.,leaf-type vegetables. It will also be noted that the opening 25 `isdirected downward toward the vessel top and thus away `from the user.The -use of a 'low heat conductivity material for the cap 36 and thedownward steam deflection provides an arrangement that is extremely safeand convenient for the user.

From the foregoing description, it will be seen that the inventionprovides a simple low cost adapter device which functions cooperativelywith a valve having freely movable elements to control the pressure of apressure cooker during non-automatic operation of the same. While apreferred embodiment of the invention has been illustrated anddescribed, it is to bc understood that the invention is not to belimited thereto but is capable of various modifications and otherembodiments.

We claim:

1. Apparatus for controlling the pressure of a pressure source,comprising a valve including a casing adapted to be placed incommunication with the pressure source and having a pressure Outlet torelieve the pressure of said source, freely movable valve means in saidcasing including a valve element subject to the pressure of said sourceand extending externally of said casing, a cap having an opening and amouth porton adapted to fit over the top of said valve, a closure memberat the mouth porton of said cap secured to the latter and formingtherewith a chamber, said closure member having an aperture toaccommodate said movable valve element, spring fingers on said closuremember for engagement with said valve to hold said cap thereon, amovable memher within said chamber comprising a disk-like portonengageable by said movable valve element and a stemlike portionprojectable through said opening, and a helical spring within saidchamber engaging said cap and said disk-like porton to prevent movcmentof said movable member and said valve element until the pressure of saidsource reaches a predetermined value less than full Operating pressure,the projection of said stem-like porton signaling the attainment of saidpressure value, said spring resisting further movcment of said valveelement unless the pressure of said source rises above the fullOperating pressure, whereupon further movcment of said element ispermitted to vent the excess pressure.

2. Apparatus for controlling the pressure of a pressure source,comprising a valve including a casing adapted to be placed incommunication with the pressure source and having a pressure Outlet torelieve the pressure of said source, freely movable valve means in saidcasing including a valve element subject to the pressure of said sourceand extending externally of said casing, a cap having an internalshoulder and a plurality of angularly-spaced internal recesses extendingfrom said shoulcomprising a disk-like porton engageable by said movablevalve element and a Stern-like porton projectable through the topopening of said cap, and a helical spring within said chamber engagingsaid cap and said disk-like porton to prevent movcment of said memberand said valve element until the pressure of said source reaches apredetermined value less than full Operating pressure, the projection ofsaid porton signaling the attainment of said pressure value, said springresisting further movcment of said valve element unless the pressure ofsaid source rises above the full Operating pressure, Whereupon furthermovcment of said element is permitted to vent the excess pressure.

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